The present invention relates to a socket for electrical parts for detachably accommodating an electrical part such as a semiconductor device (called as xe2x80x9cIC packagexe2x80x9d hereinafter).
More particularly, the present invention relates to a socket for electrical parts, which is improved for accommodating an electrical part having a center portion and a peripheral portion with bottom surfaces thereof, and having terminals mounted on the bottom surfaces, respectively.
As a conventional xe2x80x9csocket for electrical partsxe2x80x9d of this kind, there is provided an IC socket for detachably accommodating an IC package as xe2x80x9celectrical partxe2x80x9d.
The IC package includes, for example, a PGA (Pin Grid Array) type of IC package which has a rectangular-shaped package body and a large number of pin terminals mounted on a bottom surface of the package body so as to direct toward a lower side thereof.
On the other hand, the IC socket is provided with a socket body for accommodating the IC package and contact pins which are contacted to the pin terminals and separated therefrom. Moreover, the IC socket is provided with a slide plate arranged to the socket body for elastically deforming the contact pins to displace them and an operation member arranged to the socket body to be vertically movable thereto and adapted to slide the slide plate.
When accommodating the IC package, the operation member of the IC package is moved downward and the slide plate located at an original position is slid according to the downward movement of the operation member to elastically deform the contact pins so that the contact pins move away from an insertion area of the IC package.
With the contact pins being moved away from the insertion area, the IC package is mounted on the socket body to be accommodated therein and, after that, the operation member is moved upward so that the slide plate returns to the original position, thereby releasing the elastically deformation force. The release of the elastically deformation force causes the contact pins to return original positions by these elastic forces so that the contact pins contact to the terminals of the IC package so as to be electrically connected thereto.
Now, as the IC package, there is provided a composite package having the above mentioned PGA connection portion and a LGA (Land Grid Array) connection portion which are integrated with each other. The LGA connection portion has a land (metalized portion) on which predetermined terminals, such as plate terminals, are provided for connecting the IC package to a printed circuit board.
In the composite IC package, in cases where, for example, the PGA connection portion is provided on the center side of the IC package and the LGA connection portion is provided on the peripheral side thereof, it is necessary to previously provide, on the IC socket for accommodating the composite IC package, contact pins adapted to contact to the terminals of the PGA connection portion and contact pins adapted to contact to the terminals of the LGA connection portion and to secure each stability of contacting the respective contact pins to the respective terminals of the PGA and LGA connection portions.
However, according to the IC socket for accommodating the composite IC package, when the IC package is made large-sized, the IC package is easy to be warped so that, in cases where the IC package is mounted on the socket body of the IC socket, there is a possibility that the peripheral portion of the IC package rises away from the mounted surface of the socket body.
Therefore, in cases where the IC package has the configuration in that the peripheral side terminals are provided on the bottom surface of the peripheral portion thereof, there is a possibility of bringing about a gap between the peripheral side terminals and the contact pins of the IC socket, to cause a bad-contact therebetween.
It is therefore an object of the present invention is to provide a socket for an electrical part, which is capable of, even if the IC package is caused to be warped, ensuring a stability of contacting a contact pin of the socket to a terminal of the electrical part, thereby preventing the contact pin and the terminal from being instably contacted.
In order to achieve such object, according to an aspect of the present invention, there is provided a socket for an electrical part having a center portion, a peripheral portion, a first terminal mounted on the center portion and a second terminal mounted on the peripheral portion, the socket comprising:
a socket body for accommodating the electrical part;
a first contact pin arranged to the socket body and adapted to contact the first terminal of the electrical part;
a second contact pin arranged to the socket body and adapted to contact the second terminal of the electrical part; and
pressing member for pressing an upper surface of the peripheral portion towards a bottom surface side thereof.
According to the aspect of the invention, because the pressing member is comprised for pressing the upper surface of the peripheral portion of the electrical part towards the bottom surface side thereof, even if the electrical part is warped, it is possible to surely contact a contact portion of the second contact pin to the second terminal of the electrical part at a predetermined contact pressure, thereby securing the stability of contacting the second contact pin to the second terminal of the electrical part.
In an preferred embodiment of the present invention, the pressing means comprises: an operation member arranged to the socket body to be vertically movable; a slide member obliquely arranged to the socket body from an oblique upper side with respect to a surface portion of the socket body to a vicinity of the surface portion thereof, the electrical part being mounted on the surface portion to be accommodated in the socket body; a press member provided to be slidable along the slide member for pressing the upper surface of the peripheral portion; and a movement unit operatively connected to the operation member and the press member so as to move the press member obliquely upward along the slide portion when the operation member is moved downward, the movement unit being adapted to move the press member obliquely downward along the slide portion when the operation member is moved upward so as to press by the press member the upper surface of the peripheral portion of the electrical part.
According to the preferred embodiment of this aspect, as compared with a rotation-type pressing means, it is possible to ensure a pressing force to the electrical part by the press member, which is sufficient to press thereto, thereby making compact a configuration of the pressing means.
That is, assuming that the rotation-type pressing means is configured to rotate a rotation arm having at its one end portion with a press member so as to press the electrical part by the press member, when rotating the rotation arm, if the electrical part is subjected to some kind of force directed upward therefrom, because the rotation arm is easy to be rotated due to the some kind of force, it is hard to efficiently secure a sufficient pressing force.
Then, it is considerable to enlarge the urging force of a spring which urges the rotation arm, but new problems occur such that the unit becomes larger in size when we intend to secure larger operating force of the rotation arm. In addition, because of using the rotation arm having a predetermined length, it is necessary to provide a rotating space of the rotation arm, thereby causing the whole size of the electrical part to be large-sized.
On the contrary, in the preferred embodiment of this aspect, because the pressing member for pressing the electrical part is not configured to provide the rotation-type unit but to provide the slide-type unit for sliding the press member along the slide member, some kind of force directed upward from the IC package is borne to the obliquely arranged slide member of the slide-type unit so that it is possible to ensure force sufficient to hold the electrical part. Moreover, because the press member is moved in the horizontal direction, it is possible to make short the moving distance of the press member. As a result, it is unnecessary to use the rotation arm having large length and to ensure the rotation area of the rotation arm, making it possible to make compact the size of the whole socket.
In addition, when only holding the electrical part, the slide member may be arranged in a horizontal direction.
However, in the preferred embodiment, because there is the possibility that the electrical part is warped, the slide member is arranged obliquely to make the press member move obliquely along the slide member so that, even if the electrical part is warped, it is possible to surely hold the electrical part.
In another preferred embodiment of the present invention, the electrical part has a rectangular shape, the peripheral portion is at least one side surface portion of the electrical part and the pressing means comprises a latch member arranged at a position of the socket body and adapted to press a position of the electrical part corresponding to the one side surface portion of the electrical part, the pressed position of the electrical part being located at a predetermined distance away from the one side surface portion thereof toward an other side surface portion opposite to the one side surface portion.
According to the preferred embodiment of this aspect, because the at least one side surface portion of the electrical part, which is the peripheral portion, is pressed by the pressing member, and a position of the electrical part which is located at the predetermined distance away from the one side surface portion thereof towards the other side surface is pressed by the latch member, it is possible to securely press both the center portion and the peripheral portion of the electrical part which is warped.
In another preferred embodiment of the present invention, the second contact pin is formed to be elastically deformable and with a contact portion, the second contact pin being operatively connected to the operation member, and the contact portion of the second contact pin is elastically deformed to separate from the second terminal when the operation member is moved downward, and when the operation member is moved upward, is returned by an elastic force thereof to contact to the second terminal.
In still another preferred embodiment of this aspect, the first terminal is formed at a bottom side thereof with one end portion which projects. from the bottom surface of the electrical part, and the first contact pin is adapted to contact to a side portion of the projecting one end portion of the first terminal.
Other objects and aspects of the present invention will become apparent from the following description of embodiments with reference to the following accompanying drawings.